The singer was a close friend of the Prince's mother. His remake of the song "Candle in the Wind" in 1997 about Princess Diana's death became a worldwide hit. John changed the original lyrics of his song, which was initially about the death of Marilyn Monroe, to fit the princess' life. John performed it at her funeral in Westminster Abbey, where the Prince and Middleton will be wed on April 29, 2011.

Westminster Abbey was also the site of the 1947 wedding of his grandmother, Queen Elizabeth II.

Westminster Abbey, formally known as the Collegiate Church of St Peter, can seat 2,000 people and is a place of daily worship. It is also the location where 38 kings and queens were crowned and the site of 17 funerals of monarchs.

The date of the wedding falls on a Friday and will be marked as a national holiday in the United Kingdom.

"We want to mark the day as one of national celebration - a public holiday will ensure the most people possible will have a chance to celebrate on the day," British Prime Minister David Cameron said in a statement.